This invention relates generally to an adhesive mat, a system, and a method for installation of an architectural covering material to a substrate surface. The invention relates more particularly to mortarless installation of an architectural covering material such as tile utilizing an adhesive mat with layers of adhesive and release liners arranged to allow the covering material to be temporarily positioned, and re-aligned, repositioned and set as desired in a final position.
Covering materials such as tile are typically adhered to a substrate surface such as a wall or a floor using a cement-based mortar, which can be difficult and time consuming. The mortar is typically prepared by mixing a mortar powder with water until the mortar mixture has a desired pasty consistency so that the mortar mixture can be applied with a trowel. One of the drawbacks of using mortar is that mortar powder is an inherently dusty material, and while the mortar powder is being mixed with water, the dust from the mortar can cover the surrounding area. Mortar dust is generally believed to be safe, although it can be a nuisance if it is inhaled. Another problem with using mortar is that the mortar powder and water also must be mixed in a specified proportion, or else the mortar may not adequately adhere to the tile, or may cure improperly.
A wet mortar mixture is typically applied to the substrate surface with a notched trowel to form ridges and valleys in the mortar over a desired coverage of the surface. After the mortar is spread it must be used within a certain period of time, and tile must be set into the mortar before the mortar “closes,” and loses its ability to hold the tile. A person installing tile on mortar also must take great care to ensure that the tiles are properly aligned and positioned as desired, and this can be difficult, frequently requiring readjustment of tiles that have been laid on mortar. Unfortunately, mortar also has a certain adjustment time after which the positions of tiles set on it can not be adjusted. Thus, once mortar is spread, tile must be set in a final desired position on the mortar within a specified time. If too much mortar is spread before the tiles can be properly set before the mortar “closes,” or if any necessary adjustment of the positions of the tiles on the mortar has not been completed before this no longer becomes possible, the mortar and tiles must be removed, and the mortar must be discarded. In addition, the spreading of mortar commonly requires the use of many different techniques that can be critical to the ultimate success of the tile installation, such as skim coating the substrate surface, “back buttering” the tile, keeping the trowel at a specified angle in order to deliver the right amount of mortar, and the like. Another difficulty with using mortar for setting tiles is that mortar is not typically sufficient by itself to provide waterproofing. Under current practice, if tile is to be set in an area exposed to water, a separate waterproofing material typically must be added to the tile installation.
Once tile is properly set on mortar, the mortar must be allowed to cure before the tile installation can be grouted and completed. This typically can take from 4 hours (for special rapid setting mortars) to many days. Although curing commonly occurs in 16-24 hours, mortar on which tile has been set is usually allowed to cure overnight, after which the tile is substantially immovable, and is ready for grouting. Grout is typically applied by smearing grout with a rubber float across the entire surface of the set tiles and down into the grout joints between the set tiles. Excess grout is then removed as well as possible with the float, and the grout joints are “dressed” using a damp sponge.
A two-sided asphaltic membrane is currently commercially available for installing tile without mortar. However, the strength of this adhesive is not sufficient to reliably hold the tile in place, especially on vertical applications. Examples of this type of asphaltic mat with a tackier asphaltic adhesive are also too sticky for the tiles to be easily repositioned. A pressure sensitive adhesive material is also known that can be used for installing tile, and that provides dots of protruding fibers that allow the tile to be repositioned once the tile is set on the adhesive material. A double-sided adhesive tape for flooring material is also known that includes an adhesive layer with bumps and dips designed to face either a substrate surface or flooring surface. The bumps are covered by non-adhesive particles that reduce the adhesive power per unit area of the tape. Convex portions of the adhesive layer are initially placed in contact with the ground surface so that the area of contact with the substrate or flooring material is small and rendered less adherent by the non-adhesive particles, so that the adhesive tape can be moved easily. In addition, the diameter of the convex portions is 0.01-0.5 mm with spacing between ridges of 0.1-1 mm, which is too small for many tiles, which do not have a flat bonding surface. Without enough adhesive present (i.e. larger diameter) this type of double-sided adhesive tape does not provide enough surface coverage on many tiles. After the position of the flooring material is finally determined, the flooring material can be pushed toward the substrate so that both the concave and convex parts of the adhesive layer contact the substrate to firmly adhere the flooring material to the substrate. A releasing liner is provided over the adhesive layer to keep the bumps and dips of the adhesive layer intact until the adhesive layer is to be applied to the ground surface. However, in each case, an additional waterproofing must be provided if it is needed. In addition, in each case, the adhesive article is designed for use with flooring materials adhered to horizontal flooring surfaces, and not architectural covering materials that can be adhered to vertical surfaces, such as ceramic tiles adhered vertically for backsplashes, tub surrounds, and the like. Adhering flooring materials does not require the adhesive power necessary for adhering heavier, more dense tiles to vertical surfaces.
There is therefore a need for a mortarless tile installation system that does not involve the problems associated with handling and mixing a powder by a user, that can provide a secure adhesion of more dense architectural covering materials to vertical surfaces, that allows repositioning of the architectural covering materials, and that can provide waterproofing and a sufficient bond to a variety of tiles for installation orientations ranging from horizontal to vertical. The present invention meets these and other needs.